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Battle of Hypatia questions

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Re: Battle of Hypatia questions
Post by tlb   » Sat Oct 23, 2021 10:28 pm

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Relax wrote:TLB: IF I could give you a major THUMBS UP :!: on your previous post on page 1 I would. Instead I give this post as kudos instead.

tlb wrote:Thank you, that is very kind. Let me take some time to apologize for the last argument that I had with you, because we were talking at cross purposes and I am embarrassed that I did not recognize that was the case and express myself more clearly. As you probably remember, it was about the problem with the p-38 fighting at high altitude during winter over Germany. The troubles stemmed from the Allison engines needing turbochargers, because they lacked the superb supercharger used by the Merlin and Packard engines. In the extreme cold the turbo set-up had mechanical difficulties, which were not present in the much warmer air war in the Pacific. You took me as saying that the Allison lacked a supercharger (it did have a single stage one) and I kept brushing you off, because it was inadequate to get to the heights where the Army specified a turbocharger needed to be added (which was my point of interest). The problem as I should have stated it before,was not that it lacked a supercharger; but that it lacked a multi-stage supercharger that could have boosted it to the same heights as the Merlin.

Relax wrote:1) Your memory about said argument is much better than mine. :o

2) Turbo powered superchargers by efficiency standards are superior to mechanical superchargers for efficiency at all altitudes by a couple percent and MUCH superior at high altitudes by even more. Why all civilian aircraft used them. Now at some point the extra weight becomes an issue depending on range of course... SNIP my rambling: Here is a much MUCH better link... http://enginehistory.org/Piston/InterWa ... Cdev.shtml End result is that below 20,000ft little to differentiate between mechanical and turbo supercharging, but above this in terms of power, turbos increase in superiority with increasing altitude. Several NACA reports if you wish to look them up on theory and practice comparisons in the 20's and 30's between mutlitple types of supercharging. With the larger civilian airliner fleet in the 30's USA engine manufacturers were already using them everywhere with different shades of success. :lol:

2a) The USN who demanded simplicity and kaboshed all turbos especially since a lot of turbos failed early on sending shrapnel flying in all directions. USN went with 2 stage 2 speed superchargers for instance. It would be interesting to see a write up on the Brit side of development, but in all my years I have never seen one... the RR just magically appears with its 2 stage 2 speed supercharger sometime in 1942 on the Spit IX. Best I have ever read is that development of 2 stage 2 speed did not start until 1941... Maybe this was part of the Tizzard diplomatic ensemble that went to USA and the USA sent back old WWI destroyers and 2 stage 2 speed supercharger which had already been developed for the F4F Wildcat in the late 1930's? and was in service in 1940? Got me. Something that is lost to history?

3) If you go to say, http://www.wwiiaircraftperformance.org and compare power curves you will note that the mechanically driven aircraft "best speed" charts look like jigsaw puzzles, but the turbocharged 2nd stage aircraft have a ~fairly constant curve.

4) P51 designers never even contemplated using a turbo as they had the engine mount adaptable for both the Allison and the Merlin from the beginning and their first customer natively were producing the Merlin.

5) Why the P47 was superior at high altitude over any Mechanically driven engine type before or after the war when comparing prop planes. One can say it was WAAAYYY over built with dual stainless steel main wing beams, and many other stainless steel parts making it WAAY too heavy but if you just look at its engine + supercharging setup...

6) P38 got its turbos fixed, but by then it couldn't actually USE said HP as its MASSIVE design flaw of the center cockpit created massive gargantuan compressibility problems. It was so bad that if any more HP, superior propellers/spinners were added it would literally fly into its coffin corner at a mere M0.6~450mph or so and why it was never upgraded and sent to other roles. It could not dive at basic fighter speeds of the time without turning into a lawn dart due to shockwaves formed by center cockpit interfering with its twin fuselages... this is a massive problem without any way to fix. In 1940, P38 was good(top speed only, horrible maneuverability), but by end 1943 it was junk even for pure energy fighting.

7) If you do go down the rabbit hole of looking at the old test documents be keenly aware of dates of introduction, fuel used, aircraft load condition, aircraft flying condition as all tests are NOT equal. An example would be that UK testing and USAAF testing were not equal as the philosophy of the testing was different and both are valid. A good way to put this is that Boscombe down testing in the UK was interested in MAXIMUM's while USAAF at Dayton Wright Patterson was more interested in averages and minimum's and German numbers vary by translation and the major problem they had an enormous number of variants which compounds the translation problem as they had both fighter and bomber threats to deal with. Just as an example, UK testing for instance would usually test with half fuel weight, gun ports tapped closed, no aerial radio antenna, engine radiator ports closed to get a maximum speed etc and then the fanboys of said aircraft publish this number as if it is equal. USAAF testing generally had a standard aircraft off the production line with EVERYTHING in it, full fuel, radio antenna, radiator open, etc.

8) If you REALLY want to go down the weedy path of old engines and supercharging issues an excellent youtube channel is Greg's Airplanes and Automobile's where he goes into a little bit of math and quite a bit of history of different aircraft types. 95% of what he says is correct which by internet standards is high praise indeed.

Cheers!

I will not dispute that turbo is better than super and you are probably correct that early production problem were eventually fixed. However it is true that the installation of the turbo system on the early P-38 did suffer some problems that were specific to the high altitude and low temperatures of the air war over Germany in winter, for example "The P-38’s General Electric turbo-supercharger sometimes got stuck in over-boosted or under-boosted mode. This occurred mainly when the fighter was flown in the freezing cold at altitudes approaching 30,000 feet, which was the standard situation in the European air war.". The P-38J is reported to have fixed these problems. Nevertheless the P-38 was gradually replaced by P-51D's and P-47D's until there was only one group flying them at V-E Day (except in specialty roles, like reconnaissance).
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Re: Battle of Hypatia questions
Post by cthia   » Sat Oct 23, 2021 11:17 pm

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ThinksMarkedly wrote:
Relax wrote:PS: How can a normal civi ship hand off pods to ships if they supposedly have to charged with Plasma first and they do not have these plasma conduits... Inquiring minds want to know... Monica, Congo, Battles that happened off screen such as Zanzibar and the PR civil war where RFC gives hints of freighters full of pods. Explanation can be that ALL said freighters had said plasma conduits added quickly... and if you CAN add said plasma conduits so damned quickly... why could you not do so to a warships exterior out of its dorsal/ventral boat bays who ALREADY have said PLASMA conduits for said Communication Recon drones. It is not as if said conduit gets hit on the exterior if the ship cares. After all those pods are most likely already used and not your primary weapons anyways.


It might be a structural weakness problem. Civilian ships aren't armoured and expected to survive being shot at. So running plasma and/or electrical conduits through the hull is not a big deal.

On a warship, doing so could weaken the structure and thus make the ship more fragile.

But we have to remember the broadsides have dozens of tunnels, for the graser power sources, the PDLC cords and for the missile tubes. So I don't see how having smoe more for the pods' plasma taps could make this significantly worse.

Just how many limpet pods can a CA carry? We're not talking here about tractored and donkey pods, as those will affect acceleration and are expected to have a limited life-time. I'm asking about those attached to the hull on inter-system transits.

That could be solved by using beamed power at such close proximities. There shouldn't be a need to charge the pods from empty, but rather keeping them topped off. Which should be a piece of cake for beaming power to nodes on the hull of the ship. If the MA can use solar power to accomplish topping off ordnance for weeks, surely beamed power could do even better.

Son, your mother says I have to hang you. Personally I don't think this is a capital offense. But if I don't hang you, she's gonna hang me and frankly, I'm not the one in trouble. —cthia's father. Incident in ? Axiom of Common Sense
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Re: Battle of Hypatia questions
Post by Joat42   » Sun Oct 24, 2021 12:20 am

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Relax wrote:Besides: tonnage inside compensator field does not matter. Anything inside said compensator field, its mass does not matter as we saw when SD's carrying Mtons of pods on their hull at AAC 1st Manticore and not have any degradation of acceleration... Just needs a slightly bit more power RFC has said. Tonnage is a Compensator volume of space now instead of a physical tonnage as we have thought previously in the books.

It matters when you have to tractor the pods outside the wedge.

---
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Re: Battle of Hypatia questions
Post by ThinksMarkedly   » Sun Oct 24, 2021 12:33 am

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Relax wrote:Gets back to my Q... What T & P... Center of sun or surface...??? Big ass difference. Which begs the question... why can't a superconductor transmit same amount of power?


There's an easy answer to this one: because David says so. Author's Plot Hammer.

The plasma capacitors are his invention. He gets to decide how they work.

The "out" is that the "fusion" capacitors cannot be reverse charged from electricity, or are slow to do so.


They should invest in flux capacitors.
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Re: Battle of Hypatia questions
Post by ThinksMarkedly   » Sun Oct 24, 2021 12:52 am

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cthia wrote:That could be solved by using beamed power at such close proximities. There shouldn't be a need to charge the pods from empty, but rather keeping them topped off. Which should be a piece of cake for beaming power to nodes on the hull of the ship. If the MA can use solar power to accomplish topping off ordnance for weeks, surely beamed power could do even better.


We don't know if the beamed power functionality works that close to the hull in the first place. The towed pods Honor used in Fourth Yieltsin as well as the Havenite donkey design are all far from the ship, towed outside the wedge. The limpet pods are attached to it. I find far more likely you'd just run cables or plasma tubes on the hull.

As for solar power topping the Silver Bullets, please remember they charged less than the loss rate. That meant the SBs had a limited dwell time before their charge went below the minimum required for the operational parameters.

But these are not independent platforms that also have limited solar panel area due to stealth. These would be attached to the ship and its power generation capacity. Do remember ships have an extra reactor for redundancy, so they can surely generate enough power to power the pods shortly before ditching them for a massive alpha strike.

I can't find an in-universe reason so far why they shouldn't have carried pods to Hypatia, especially if the back-of-the-envelope calculations are correct and they could have brought another 6000 missiles. Only Plot Hammer explains.
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Re: Battle of Hypatia questions
Post by cthia   » Sun Oct 24, 2021 7:23 am

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ThinksMarkedly wrote:
cthia wrote:That could be solved by using beamed power at such close proximities. There shouldn't be a need to charge the pods from empty, but rather keeping them topped off. Which should be a piece of cake for beaming power to nodes on the hull of the ship. If the MA can use solar power to accomplish topping off ordnance for weeks, surely beamed power could do even better.


We don't know if the beamed power functionality works that close to the hull in the first place. The towed pods Honor used in Fourth Yieltsin as well as the Havenite donkey design are all far from the ship, towed outside the wedge. The limpet pods are attached to it. I find far more likely you'd just run cables or plasma tubes on the hull.

As for solar power topping the Silver Bullets, please remember they charged less than the loss rate. That meant the SBs had a limited dwell time before their charge went below the minimum required for the operational parameters.

But these are not independent platforms that also have limited solar panel area due to stealth. These would be attached to the ship and its power generation capacity. Do remember ships have an extra reactor for redundancy, so they can surely generate enough power to power the pods shortly before ditching them for a massive alpha strike.

I can't find an in-universe reason so far why they shouldn't have carried pods to Hypatia, especially if the back-of-the-envelope calculations are correct and they could have brought another 6000 missiles. Only Plot Hammer explains.

I would think that beamed power would be more effective the closer the recipient, as in every other application of power transference I can think of. The shorter the power cords the more efficient the transference. The shorter the power lines in a municipality the less need there will be of a step-up transformer.

Late edit: The SB's were charged less than the loss rate because they were in-use and drawing power while they were being charged. Pods limpeted to the hull are dormant and shouldn't be losing power beyond their natural discharge rate.

I think at Hypatia the lack of pods may have been somewhat academic. The RMN didn't normally take pods along unless they were expected to be needed. Hypatia was not a place where pods were expected to be needed. Remember, Hypatia was not an enemy of the SL thus it wasn't expected to be a SLN target. Therefore, there was no need to expect a formidable force to be found there.

You know, I never suspected that the pods 'use them or lose them' clause was also tied to their 'standby-time.' Which is the one main disadvantage of smartphones to the old-fashioned flip phones. The flip phones had a standby time of days to weeks, not hours.

Son, your mother says I have to hang you. Personally I don't think this is a capital offense. But if I don't hang you, she's gonna hang me and frankly, I'm not the one in trouble. —cthia's father. Incident in ? Axiom of Common Sense
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Re: Battle of Hypatia questions
Post by Jonathan_S   » Sun Oct 24, 2021 9:00 am

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Relax wrote:2) Turbo powered superchargers by efficiency standards are superior to mechanical superchargers for efficiency at all altitudes by a couple percent and MUCH superior at high altitudes by even more. Why all civilian aircraft used them. Now at some point the extra weight becomes an issue depending on range of course... SNIP my rambling: Here is a much MUCH better link... http://enginehistory.org/Piston/InterWa ... Cdev.shtml End result is that below 20,000ft little to differentiate between mechanical and turbo supercharging, but above this in terms of power, turbos increase in superiority with increasing altitude. Several NACA reports if you wish to look them up on theory and practice comparisons in the 20's and 30's between mutlitple types of supercharging. With the larger civilian airliner fleet in the 30's USA engine manufacturers were already using them everywhere with different shades of success. :lol:

2a) The USN who demanded simplicity and kaboshed all turbos especially since a lot of turbos failed early on sending shrapnel flying in all directions. USN went with 2 stage 2 speed superchargers for instance. It would be interesting to see a write up on the Brit side of development, but in all my years I have never seen one... the RR just magically appears with its 2 stage 2 speed supercharger sometime in 1942 on the Spit IX. Best I have ever read is that development of 2 stage 2 speed did not start until 1941... Maybe this was part of the Tizzard diplomatic ensemble that went to USA and the USA sent back old WWI destroyers and 2 stage 2 speed supercharger which had already been developed for the F4F Wildcat in the late 1930's? and was in service in 1940? Got me. Something that is lost to history?

[snip] And to be fair the USN expected (and more importantly, was correct in that expectation) that most of their combat wouldn't be at especially high altitude. So if you're not going to be fighting above 20,000 feet you don't need the turbo over the supercharger.

Also, looking at the engine + turbo diagrams for a P-47 or P-38 the turbos and related components for a WWII era aircraft engine seem huge and you need a lot of volume to fit them and all their ductwork. It looks like most of the fuselage behind a P-47's cockpit is taken up by its turbo. As such big beasts (compared to engine driven superchargers) they seem easier to fit onto multi-engine bombers or transports than onto your typical fighter or naval strike aircraft (and the USAAF used them far more extensively on bombers).

So compactness and lower combat altitudes seem to say that the USN probably made the right choice in eschewing any turbos in its carrier aircraft.
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Re: Battle of Hypatia questions
Post by Relax   » Sun Oct 24, 2021 11:08 am

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Jonathan_S wrote:[snip] So if you're not going to be fighting above 20,000 feet you don't need the turbo over the supercharger.

Also, looking at the engine + turbo diagrams for a P-47 or P-38 the turbos and related components for a WWII era aircraft engine seem huge and you need a lot of volume to fit them and all their ductwork. It looks like most of the fuselage behind a P-47's cockpit is taken up by its turbo.


Actually, if you look at a cutaway drawing of Corsair, Hellcat, or any other aircraft of that period, you will note that behind the pilot the fuselage is completely empty. The problem was never fuselage volume per se, but rather How you get the ducting from behind the pilot TO the engine in front. This aspect DOES increase fuselage height. Also, weight of said ducting which has HOT gases needs to be heavy steel or stainless steel and this adds up. Now if you are a carrier based plane and your biggest difficulty is LANDING on an aircraft carrier without crashing killing yourself and your buddies, extra weight which does not help in landing is not exactly your friend. Now add that there are no RADAR stations over oceans so one does not have to fly HIGH for advantage as no one can see you coming unless you get severely unlucky via a scout plane. Then also add that planes for carriers are relatively short ranged even if they are in position over the carriers for protection as waiting an hour as you circle just so you can land is not exactly uncommon in WWII carrier ops. Running out of fuel is not uncommon at all. Makes one seriously question modern carriers whose aircraft have even LESS fuel and ability to stay on station compared to WWII aircraft... There are no pressers tractors for landing on carriers like there are on CLAC's ... :o

Oh just as a point of interest: Today, your typical business jet cruises around 500mph, has 2 jet engines which generally speaking produce a maximum of about 2000lbs of thrust each so we can roughly speaking state that at cruise they require about 1500lbs of thrust and these business jets have same Empty weight as a Heavy WWII fighter. The P47's late war turbo, which is not a jet engine exactly(but same principles) was projected to have well over 700lbs of thrust and maybe as high as 1000lbs of thrust. The war ended before the Superbolt was ever put into production. It would have had superior speed, climb rate etc to the Original jets of the time. Of course crude jet engines is what held them back, not their designs for speed as P80 which originally had roughly speaking a top speed no greater than the P47, would in a couple years of jet turbine development hit 600+mph.
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Re: Battle of Hypatia questions
Post by Jonathan_S   » Sun Oct 24, 2021 9:30 pm

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Relax wrote:
Jonathan_S wrote:[snip] So if you're not going to be fighting above 20,000 feet you don't need the turbo over the supercharger.

Also, looking at the engine + turbo diagrams for a P-47 or P-38 the turbos and related components for a WWII era aircraft engine seem huge and you need a lot of volume to fit them and all their ductwork. It looks like most of the fuselage behind a P-47's cockpit is taken up by its turbo.


Actually, if you look at a cutaway drawing of Corsair, Hellcat, or any other aircraft of that period, you will note that behind the pilot the fuselage is completely empty.

Well, the Mustang did seem to have a fair bit of stuff back there, though it may well be the exception.
Even the early models seems to have had the radios, batteries, and engine cooling radiator back there (fed by air from the belly scoop), and then later they stuck an extra fuel tank back there too (though IIRC that changed the CG enough to make handling a bit squirrely until you'd burned off a fair bit of it -- and also I want to say that tank wasn't self-sealing; unlike the rest. Another reason to use it up first)

But looking at the Corsair it doesn't seem to have had much back there - radio equipment, a long shock absorber for the tail hook, and some hardware related to raising and lowering the tail wheel. I didn't dig into the Hellcat, but I'm willing to believe it has similar amounts of void space back there.
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Re: Battle of Hypatia questions
Post by tlb   » Mon Oct 25, 2021 8:52 am

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Jonathan_S wrote:Well, the Mustang did seem to have a fair bit of stuff back there, though it may well be the exception.
Even the early models seems to have had the radios, batteries, and engine cooling radiator back there (fed by air from the belly scoop), and then later they stuck an extra fuel tank back there too (though IIRC that changed the CG enough to make handling a bit squirrely until you'd burned off a fair bit of it -- and also I want to say that tank wasn't self-sealing; unlike the rest. Another reason to use it up first).

"Lots of planes could carry drop tanks: P-47, P-40, P-38, etc.," says James Gibson, former MP&P Engineer at Boeing, says on Quora.

"The real secret to the Mustang’s range was not the laminar flow control wing, or the Merlin engine. It was the addition of a fuselage tank behind the cockpit halfway through production of the P-51B. This additional internal tank increased fuel capacity by 85 gallons: original P-51Bs only had 184 gallons in the wings. The addition increased total fuel to 269 gallons or some 30%. Further adding two 75 gal drop tanks you reached 419 gallons. The later D&H models carried 110 gal drop tanks for 489 gallons.

‘But when you carried so much fuel you had to be aware of which tanks you were using at which point in the flight. On take-off you used the rear fuselage tank. This tank effected the center of gravity of the plane. You didn’t want to tangle with a 109 or a Focke Wulf when carrying fuel in the rear tank. So you burned it first and then switched to the drop tanks about halfway to Berlin.

You would then burn off the drop tanks, hopefully before engaging enemy fighters. But if they struck early you could drop those tanks and thus be clean and maneuverable. This was the fight profile that allowed the Mustangs maximum range and best performance when over target."

And the presence of the turbocharger explains why you could not pull this same trick to add range to the P-47.
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